Digital three-dimensional manufacturing, also known as digital additive manufacturing, is a process of making a three-dimensional solid object of virtually any shape from a digital model. Three-dimensional printing is an additive process in which one or more printheads or ejector heads eject successive layers of material on a substrate in different shapes. The substrate is supported either on a platform that can be moved three dimensionally by operation of actuators operatively connected to the platform, or the printhead or printheads are operatively connected to one or more actuators for controlled movement of the printhead or printheads to produce the layers that form the object. Three-dimensional printing is distinguishable from traditional object-forming techniques, which mostly rely on the removal of material from a work piece by a subtractive process, such as cutting or drilling.
In some three-dimensional printing systems, certain intermediate processing steps and post-processing steps are performed in addition to the ejection of layers of material. For example, a substrate may be planarized, cured, or cooled between ejecting material layers or after completing a printed object. Three-dimensional printing systems have been developed that have multiple processing stations, each configured to perform different processes involved in manufacturing a finished three-dimensional object. Such multi-station three-dimensional printing systems often comprise a track that guides a cart from one processing station to another. The cart rides along the track to convey a substrate between processing stations. The cart is generally moved along the track by a motive force generated by a motor such as a linear synchronous motor (LSM) or a linear induction motor (LIM). LSM and LIM technology allows for quick and reliable motion of the cart between stations, but does not provide enough force and resilience to operate under the various loads that the cart may encounter at the various processing stations. What is needed is a three-dimensional printings system that takes advantage of the speed and flexibility of LSM and LIM technology while also providing accurate motion at processing stations that is resilient against weight, speed, and load changes associated with the variety of processing steps required to manufacture a finished three-dimensional object.